Decelerator



T. A. M GILL DECELERATOR July 2, 1963 2 Sheets-Sheet 1 Filed April 12, 1962 7d U 4 1 fl #0 0 a a L 4 L W WM 4 H WU M T. A. M GILL DECELERATOR July 2, 1963 2 Sheets-Sheet 2 Filed April 12, 1962 3,095,955 Patented July 2, 1963 3,095,956 DECELERATOR Thomas A. McGill, South Hamilton, Mass, assignor to J. W. Greer Company, Wilmington Mass, :1 corporation of Massachusetts Filed Apr. 12, 1962, Ser. No. 187,005 3 Claims. (Cl. 193-35) The present invention relates to roller conveyors and, 7

more particularly, to an improved decelerator device for retarding free-running loads on an inclined roller conveyor.

Inclined conveyors of the type here referred to are employed for conveying substantial loads, such as pallets which may be of a large size, and heavily loaded. In a popular size the pallet may measure 3 feet by 3 feet and is loaded with up to 300 or more packages reaching a height of about 6 feet.

It will be evident that a pallet loaded in this fashion must be carefully controlledat all times to prevent bumps or pressures which couldresult in the disarrangement and collapse of the load. The pitch employed must be sufficient to overcome frictional resistance and to insure continued movement of the pallet. To prevent the loaded pallet from running away, decelerator rollers may be employed which check any tendency of the pallet to accelerate while permitting continued movement at a reasonable rate.

The roller decelerating device which forms the subject matter of the present invention is of the general type which comprises relatively stationary and rotating elements, connected in such a manner to be acted upon by a damping medium which tends to resist any undue increase of velocity of the rotating element beyond a permissible maximum value.

The illustrated device comprises two concentric tubes, one of which is fixedly supported and the other of which is connected to be rotated with the passage of a load over the inclined conveyor.

The extent of the damping action produced by any increase in velocity of the rotated element depends upon the relationship of the clearance provided between the resistance producing faces of the rotating and stationary elements, the area of said surfaces, and the viscosity of the medium employed.

It is a principal object of the invention to provide an improved organization of an inclined roller conveyor having as an element thereof a novel roller decelerator device which is readily detachable from the conveyor and shiftable from one to another position thus making possible an accurate and sensitive control of the conveyor operation according to the weight and sliding characteristics of the loads carried on the conveyor.

It is a further object of the invention to provide an improved roller decelerating device for use with an inclined roller conveyor, which is simple and effective in construction and is well adapted for checking and for controlling the momentum of heavy loads on the inclined conveyor.

With these and other objects in view as may hereinafter appear the several features of the invention will readily be appreciated from the following description taken in connection with the accompanying drawings in which:

FIG. 1 is a somewhat diagrammatic plan view of a portion of an inclined conveyor having decelerating roller units in accordance with the invention;

FIG. 2 is a side View of substantially the parts shown in FIG. 1 indicating the manner in which the progress of a loaded pallet is controlled by said rollers on the inclined conveyor;

FIG. 3 is a sectional view taken on a line 3-3 of FIG.

ll illustrating on a substantially larger scale one of applicants decelerating roller devices;

FIG. 4 is a detail view partly in section illustrating particularly the construction of the centrally disposed decelerator device illustrated in FIG. 3; and

FIG. 5 is a sectional view taken on a line 5-5 of FIG. 4.

The apparatus shown in the drawings comprises an inclined roller conveyor which is particularly adapted for transferring heavy loads as, for example, heavily loaded pallets along an inclined path which is given just suffioient pitch to cause the mass to move.

Referring specifically to the drawings, the conveyor shown consists of two parallel inclined tracks 10 and 12, consisting of supporting rails 14, '15 and 16, 17 respectively set on edge in parallel relation and bored at intervals to provide bearing support for a series of rollers 18 and their pivot shafts 20.

It will be understood that a portion only of the conveyor is shown which, however, is believed sufficient to illustrate the connection of the present invention therewith.

In the illustrated construction a separate decelerator device, generally designated at 24 in FIG. 1, is provided at each of a plurality of spaced intervals along the length of the conveyor. As hereinafter more specifically pointed out the individual decelerating devices are constructed and arranged to be incorporatedinto the conveyor in such locations and in such frequency as may be determined by the characteristics of the loads which are expected to pass over the conveyor. may thus be readily activated or may be withdrawn according to the requirements of the particular job the conveyor is called upon to perform.

Referring to FIG. 3, which specifically illustrates one such roller'decelerator assembly, the assembly includes two rollers 25, 26 mounted in axial alignment with one another on the inclined tracks 10 and 12, respectively both connected to the decelerator device 24. It will be noted that the rollers 25, 26 are of substantially larger diameter than the decelerator device 24. The rollers 25, 26 are provided with non-slip load bearing surfaces which may be produced, for example, by mounting said rollers.

to project slightly above the plane of the remaining rollers 18 of the series, or by providing the rollers 25, 26 with friction-surfaces for engagement with the bottom surfaces of the pallets passing over the conveyor. In the illustration shown, it is assumed that the standard rollers '18 have a diameter of 2 /2 inches, are 8 inches long, and that the two tracks vIll and 12 are spaced from one another so that the rollers of each series will support a pallet having a width of 3 feet at each edge. The rollers 25, 26

are 3 /2 inches in diameter and have bearing supports the rails :14, 15 located so that the load contact surface of each roller 25, 26 is at or slightly above the plane of the load contact surfaces of rollers 18.

The roller decelerator device provided in accordance with the presents invention as best shown in FIGS. 4 and- 5 consists of two concentric tubes 28, 30, the outer tube 28 being fixed in position and acting as a stator, and the inner tube 30 being connected at its two ends to rotate with the rollers 25', 26 as a rotor. The outer tube is maintained in an angularly stationary position by means of a structure including a V-shaped trough 32 which is disposed immediately beneath the de-celerator device and is fastened at its two ends to the tracks 10 and 12. Pin 34, screw threaded into the under side of the outer tube 28, extends downwardly against the sides of the trough 32 to prevent rotational movement of the outer tube. The inner tube or rotor 30 at its Individual roller deceler-ator devices right hand end as shown in FIG. 4 is provided with a shaft extension connected. by means of a coupling 36 to the supporting shaft 38 for roller 26. A cotter pin 40 is provided to pin the coupling 36 to the shaft 38. A transverse pin 42 in the end of the rotor shaft extension 35 engages in a V-shaped slot 44 in the coupling 36 causing these parts to turn as a unit. At its left hand end as shown in FIG. 4, a shaft extension 45 of the inner tube or rotor 30 is connected by means of a coupling 46 with the second roller 25. The coupling 46 is connected by means of a transverse locking pin 49 to the supporting shaft 50 for roller 25. At its inner end the coupling 46 is provided with a T-shaped slot 52 which receives a transverse pin 54 carried by shaft extension 45, allowing some lost motion between the rotor 30 and roller 25. The outer tube or stator 28 is supported on the bearing shaft extensions 35 and 45 of the inner tube or rotor 30, being provided at each end with a plug 56 having an outwardly flanged end 58 overlying the end of the outer tube 28. Each plug 56 is bored to receive the respective shaft extension 35 .or 45 of the inner tube 30, and is fitted on its inner face with a washer which acts a fluid seal so that the fluid employed as a retarding medium may be securely contained within the outer tube or stator 28.

It will be noted further that the inner tube 30 takes the form of a hollow cylinder and is provided at each end with apertures 62 to permit a free circulation of the damping medium through and around the inner tube or rotor 30. In order to maintain an even distribution of'the damping medium throughout the space provided between the external peripheral surface of the inner tube and the internal peripheral surface of the outer tube, helical grooves '64 are formed in the surface of the inner tube which serve to carry said medium along the length thereof. In the preferred embodiment of themvention shown, it is contemplated that a silicone substance will be employed as the damping medium between the stator 28 and rotor 30, said substance having the property of maintaining a constant viscosity for a wide range of temperature variations so that opera-- with is shown which is adapted for the handling of heavy loads which may vary. over substantial limits between a minimum of less than a thousand pounds to a maximum of several thousand pounds per load. It will be understood that the details of the several identical decelerator devices employed, including the size of the braking surfaces, the clearance therebetween, and the viscosity characteristics of the damping fluid will have been stabilized to provide a decelerator device suitable for use with pallet loads within the limits above stated. The incline of the conveyor is set at an angle which is just sufiicient to cause the pallet to move.

j The decelerator device limits the speed of rotation of the rotor element thereof to a desired maximum linear rate when acting to retard a full pallet load. The speed of rotation when conveying a partially loaded pallet will be something less than said allowable maximum. However, since the device has a damping action rather than a frictional braking action, the lightly loaded pallet will still move but at a reduced speed.

In order to provide for variations in the amount of braking effect which may be required under given conditions, it is contemplated that a substantial number of decelerating stations will be provided along the length of the conveyor which are readily adapted to be activated or deactivated as deSired and thus to increase or derails of the tracksltl and 12, it will be understood that a greater or smaller number of such stations may be provided along the length of the conveyor. It is here assumed that the location of such decelerating stations at'the location of each fourth pair of rollers will provide the maximum damping 0r braking elfect which may be desired. Conditions which might require the addition or subtraction of activated stations on any given section of the conveyor would include variations in the size of pallet and load therein or the relatively smaller amount of checking which may be required where the loaded pallet is required to coast along a substantial length of a guideway. In order to withdraw any one of the individual units, a cotter pin 40 is withdrawn permitting the associated coupling to he slid outwardly thus releasing the decelerator unit which is now withdrawn manually in an upward direction.

The illustrated construction has the specific advantage that the decelerator device does not engage against and carries no part of the bearing load of the pallet designated at 72, for the reason that the external diameter of the stator cylinder 28 is substantially. less than that of the decelerator rollers 25, as. The construction shown provides for the particularly efficient use of the damping fluid which is distributed evenly along the length of the opposed peripheral surfaces of'the rotor and stator cylinders by means of the spiral grooves 70 formed in the inner peripheral surfaces of the rotor cylinder 30. As shown, the silicone substance is permitted to circulate freely through the interior of the inner cylinder or rotor cylinder 30, through end passages 62, around the ends of said cylinder.

While distribution of the damping fluid along the peripheral damping surfaces is here eifected by means of the spiral grooves 70, it will be understood that such distribution is readily accomplished by the use of any suitable means as, for example, by the use of perforations in the walls of the rotor cylinder, the fiuid in this instance being fed through such perforations from the hollow interior of the cylinder.

While the invention in the preferred embodiment shown contemplates the use of a double track conveyor, it will be understood that the invention is equally applicable to a single track conveyor in which decelerator roller devices wouldbe substituted at intervals for the ordinary idler rollers of the conveyor. The decelerator device would then be mounted on or adjacent to the supporting rails for the idler rollers and would be connected with an associated decelerator roller by any suitable means such as a driving connection interposed between the decelerator roller and the rotor cylinder of the decelerator unit.

It will be further understood that features of the invention relating particularly to the use of concentrically mounted cylinders of which the inner surface of one cylinder is so spaced from the outer surface of the other cylinder, and the viscosity of a damping fluid introduced therebetween is so chosen as to effect a shearing of said fluid and thereby to damp the relative rotational movement of said cylinders, are of broad application and are therefore not limited to the particular embodiments shown except as expressly set forth in the appended claims.

The invention having been described what is claimed 1. In a roller conveyor having a series of idler rollers disposed in sequential parallel relation for transferring a load over said rollers, the combination of a plurality of decelerator rollers spaced among said idler rollers, each said decelerator roller being constructed and arranged to have a non-slip load bearing surface, and a decelerator unit comprising a shaft, a rotor cylinder secured to said shaft, a stator cylinder disposed concentrically over said rotor cylinder and having fluid tight bearings at each end thereof on said shaft, said concentric stator and rotor cylinders having cooperating dam-ping peripheral surfaces spaced from one another so that increasing relative velocity between said surfaces produces a damping effect therebetween, means on said conveyor for supporting said shaft on the same axis with a selected one of said decelerating rollers, means for connecting said shaft to said axially aligned decelerator roller, means securing said stator cylinder in fixed angular position on said conveyor, and a damping fluid disposed between the peripheral damping surfaces of said cylinders of a viscosity chosen to produce said damping effect.

2. In a roller conveyor, two parallel series of idler rollers adapted for the transfer of a load over said rollers, the rollers of one of said series being separated laterally from the rollers of the other said series, and at least one decelerator roller unit in said series of units comprising a decelerator roller in each of said series disposed one opposite the other in axial alignment and constructed and arranged to have a non-slip load bearing surface, and a fluid operated roller retarding device disposed between and attached to each of said decelerator rollers comprising a shaft, a rotor cylinder secured to said shaft, a stator cylinder disposed concentrically over said rotor cylinder being of smaller diameter than said decelerator rollers and having fluid tight bearings at each end thereof on said shaft, said concentric stator and rotor cylinders having cooperating damping peripheral surfaces spaced from one another so that increasing relative velocity between said surfaces produces a damping effect therebetween, means on said conveyor for supporting said shaft on the same axis with and between said decelerating rollers, means for connecting said shaft to said axially aligned decelerator rollers, means securing said stator cylinder in fixed angular position on said conveyor, and a damping fluid disposed between the peripheral damping surfaces of said cylinders of a viscosity chosen to produce said damping effect.

3. A roller conveyor having a roller decelerator unit according to claim 2 in which a detachable coupling is provided between each end of said shaft and the adjacent axially aligned decelerator roller, and the means for angularly supporting said stator cylinder comprises an abutment on the cylinder and a cooperating stationary abutment on the conveyor freely separable to permit the disassembly of said unit from the conveyor.

References Cited in the file of this patent UNITED STATES PATENTS 2,419,045 Whittaker Apr. 15, 1947 2,618,370 Orwin Nov. 18, 1952 2,649,177 Anderson Aug. 18, 1953 2,766,849 Rudiger Oct. 16, 1956 2,949,863 Cozzoli Aug. 23, 1960 2,979,177 Sullivan Apr. 11, 1961 3,017,007 McGrath Ian. 16, 1962 

1. IN A ROLLER CONVEYOR HAVING A SERIES OF IDLER ROLLERS DISPOSED IN SEQUENTIAL PARALLEL RELATION FOR TRANSFERRING A LOAD OVER SAID ROLLERS, THE COMBINATION OF A PLURALITY OF DECELERATOR ROLLERS SPACED AMONG SAID IDLER ROLLERS, EACH SAID DECELERATOR ROLLER BEING CONSTRUCTED AND ARRANGED TO HAVE A NON-SLIP LOAD BEARING SURFACE, AND A DECELERATOR UNIT COMPRISING A SHAFT, A ROTOR CYLINDER SECURED TO SAID SHAFT, A STATOR CYLINDER DISPOSED CONCENTRICALLY OVER SAID ROTOR CYLINDER AND HAVING FLUID TIGHT BEARINGS AT EACH END THEREOF ON SAID SHAFT, SAID CONCENTRIC STATOR AND ROTOR CYLINDERS HAVING COOPERATING DAMPING PERIPHERAL SURFACES SPACED FROM ONE ANOTHER SO THAT INCREASING RELATIVE VELOCITY BETWEEN SAID SURFACES PRODUCES A DAMPING EFFECT THEREBETWEEN, MEANS ON SAID CONVEYOR FOR SUPPORTING SAID SHAFT ON THE SAME AXIS WITH A SELECTED ONE OF SAID DECELERATING ROLLERS, MEANS FOR CONNECTING SAID SHAFT TO SAID AXIALLY ALIGNED DECELERATOR ROLLER, MEANS SECURING SAID STATOR CYLINDER IN FIXED ANGULAR POSITION ON SAID CONVEYOR, AND A DAMPING FLUID DISPOSED BETWEEN THE PERIPHERAL DAMPING SURFACES OF SAID CYLINDERS OF A VISCOSITY CHOSEN TO PRODUCE SAID DAMPING EFFECT. 